Tánaiste Joan Burton has rejected claims from within her own party that a referendum on repealing the Eighth Amendment is a "red-line issue".

The Labour Party leader said a vote on further liberalising the country's abortion laws would be discussed with Fine Gael during any future Programme for Government negotiations.

But she moved to play down suggestions that a referendum would be a pre-condition for a second term between Fine Gael and Labour.

"In the Labour Party we have a long-standing position in relation to the Eighth Amendment," Ms Burton said.

"Hopefully, we will be a key part in the next government and certainly we will be discussing that as part of the negotiations, but I certainly never use terms like 'red line'."

Labour sources expressed concern at remarks made by the Taoiseach in Limerick in relation to repealing the Eighth Amendment.

Mr Kenny insisted that Fine Gael will have no commitment in its election manifesto to hold a referendum on the amendment that protects the rights of the unborn and prevents abortions in cases of fatal foetal abnormalities.

It remains to be seen whether the abortion issue will feature in the Fine Gael manifesto.

However, a Labour strategist said last night that there was a "clear expectation" among the grassroots that a referendum would be held in the lifetime of the next government.